This thesis has focused on an aircraft schedule and network design problem that involves multiple types of aircraft and flight service. First, this thesis expands a business model for integrating on-demand flight services with the traditional scheduled flight services. Then, this thesis proposes a three-step approach to the design of aircraft schedules and networks from scratch. After developing models in the three steps and creating large-scale instances of these models, this dissertation develops iterative algorithms and subproblem approaches to solving these instances, and it presents computational results of these large-scale instances. To validate the models and solution algorithms developed, this thesis compares the daily flight schedules that it designed with the schedules of the existing airlines. In addition, it discusses the implication of using new aircraft in the future flight schedules. Finally, future research in three areas--model, computational method, and simulation for validation--is proposed.

Denna magisteruppsats i ekonomisk historia har som syfte att utforska varför den svenska bilparken är mer bränslekrävande än genomsnittet i Europa, samt att identifiera de historiska processer som påverkat formandet av den svenska bilparken. Tidigare miljöinriktad forskning inom ekonomisk historia har fokuserat på strukturomvandling och institutionell förändring inom industri- och hushållssektorn. Denna studie utforskar den privata transportsektorn genom att studera Volvo som varit tongivande i att forma sammansättning av den svenska bilparken. Genom att studera två av Sveriges största biltidningar – Teknikens värld och Volvos egen konsumenttidning, Ratten – samt årsberättelser och hållbarhetsrapporter från Volvo, har historien om varumärket Volvo och Volvos relation till miljön utforskats.  Volvo antog ’kvalitet’ och ’säkerhet’ som kärnvärden vid starten 1927. ’Omsorg om miljön’ lades till som ett tredje kärnvärde 1972 vilket antas vara av relevans för hur Volvo byggt sin identitet. Hur Volvo tolkat ’omsorg om miljön’ i relation till sitt varumärke och hur det integrerats i företagets produktionsprocesser är utgångspunkter för uppsatsens undersökande del som sträcker sig från 1972 till 2014.  Resultatet visar på att begreppet ’miljö’ har omtolkats av Volvo och följt den samhälleliga diskursen ganska väl. Från att handla om den lokala ’arbetsmiljön’ och det som kopplas därtill, till att handla om regionala utsläpp av partiklar för att till sist innefatta ett globalt perspektiv. Resultatet visar också att Volvo på grund av höga kostnader för arbetare och en stor efterfrågan från den amerikanska marknaden drivits till att producera stora och dyra bilar som drar mycket bränsle. På grund av att Volvo inte kunnat konkurrera med höga försäljningsvolymer har man istället satsat på säkra och hållbara bilar som kunnat bringa högre vinstmarginaler.  Efter krisen på 1990-talet och ett byte av ledarskap från Pehr G. Gyllenhammar till Sören Gyll, visar resultatet att ’omsorg om miljön’ fick en mer framskjuten roll i Volvos varumärkesbyggnad. Samtidigt beslutades att Volvo skulle ta ytterligare steg mot att tillverka bilar i premiumsegmentet vilket var svårt att kombinera med miljöhänsyn vad gäller bränsleförbrukning.  Slutsatserna som dragits från denna uppsats är att Volvo efter andra världskriget lyckades skaffa sig en ’pionjärsfördel’ – pioneering advantage – genom en stark introduktion av PV 444/544-modellerna på 1940- och 1950-talet och att man sedan kunnat använda denna fördel för att omtolka svenskars preferenser att välja bränslekrävande bilar. Detta innebär att företag, om de vill, har möjlighet att styra konsumenter mot att välja bättre miljöanpassade produkter. I uppsatsen argumenteras för att avsättningsmarknader spelar stor roll för möjligheten för företag att ställa om produktionen till att leverera ’grönare’ produkter.

Understanding how households make decisions with regards to their vehicle fleet based on their demographics, socio-economic status and travel patterns is critical for managing the financial, economic, social and environmental health of cities. Vehicle fleets therefore form a component of the Integrated Land Use, Transportation and Environment (ILUTE) modelling system under development at the University of Toronto. ILUTE is a year-by-year agent-based microsimulation model of demographics, land use and economic patterns, vehicle fleet decisions and travel choices in the Greater Toronto and Hamilton Area. This thesis extends previous work that modelled the quantity, class and vintage of vehicles in ILUTE households. This revised model offers three key improvements: transaction decisions are made sensitive to travel patterns, fuel costs are better represented, and vehicle purchases are considered in the context of the overall household budgeting. Results are promising, but further model validation is required. Potential extensions of the research are discussed.

Šiame baigiamajame darbe išanalizuotas bendrovės turimas lokomotyvų parkas, jų sudėtis, amžius, techninės charakteristikos. Apžvelgtos lokomotyvų parko atnaujinimo programos. Atlikta prekinių-magistralinių lokomotyvų gedimų analizė iki parko atnaujinimo ir po jo. Pateikta krovinių vežimų analizė iki 2007 metų bei prognozė iki 2030 m. Apžvelgti AB „Lietuvos geležinkeliai“ vykdomi bei numatomi įgyvendinti infrastruktūros projektai, kurie gali turėti įtakos lokomotyvų parko kitimo ilgalaikei strategijai. Remiantis teorinėmis formulėmis ir informacija, nustatytomis prielaidomis bei lokomotyvų apyvartos analize buvo išvesta formulė, pagal kurią skaičiuoti turimų, numatytų įsigyti bei modernizuotų lokomotyvų pajėgumai parko kitimo perspektyvoje ir palyginti su prognozuojamu krovinių srautų didėjimu. Identifikavus reikalingus lokomotyvų pajėgumus ir jų papildomą kiekį perspektyvoje pasiūlytas racionaliausias lokomotyvų parko kitimo ilgalaikės strategijos variantas. / The locomotive park, its composition, age and technical characteristics of stock company are analyzed in this master’s dissertation. There are reviewed renewal programmes of Locomotive Park. Here have been analyzed breakdowns of freight locomotives till and after renewal program. Here have been analyzed freight haulage till 2007 year and forecast till 2030 year. There is reviewed JSC “Lietuvos geležinkeliai“ supposed infrastructure project which could influence to the locomotives fleet long-rate strategic. Considering to theoretical formulas and information, selected presumptions and locomotive work analyses was educed formula in accordance with was calculated locomotives potential work in the future and compared with forecast of freight haulage. Here have been identified the demand and amount of locomotive work in the prospect and suggested most rational development prospects of the locomotive park of JSC "Lietuvos geležinkeliai".

Understanding how households make decisions with regards to their vehicle fleet based on their demographics, socio-economic status and travel patterns is critical for managing the financial, economic, social and environmental health of cities. Vehicle fleets therefore form a component of the Integrated Land Use, Transportation and Environment (ILUTE) modelling system under development at the University of Toronto. ILUTE is a year-by-year agent-based microsimulation model of demographics, land use and economic patterns, vehicle fleet decisions and travel choices in the Greater Toronto and Hamilton Area. This thesis extends previous work that modelled the quantity, class and vintage of vehicles in ILUTE households. This revised model offers three key improvements: transaction decisions are made sensitive to travel patterns, fuel costs are better represented, and vehicle purchases are considered in the context of the overall household budgeting. Results are promising, but further model validation is required. Potential extensions of the research are discussed.

Den svenska handelsflottan har de senaste åren varit utsatt för massiva utflaggningar vilket har lett till att många sjömän har fått gå i land eller sökt arbete under annan flagg. Trots problemen med utflaggning och en potentiell minskad arbetsmarknad har sjöingenjörsprogrammet de senaste åren inte haft några större problem att fylla sina utbildningsplatser. Framtiden är fortsatt oviss och konkurrensen från andra sjöfartsnationer ökar. Syftet med denna undersökning var att undersöka vilka bakomliggande attityder och förväntningar som gjorde att studenter år 2013 valde att börja studera på det fyra åriga sjöingenjörsprogrammet i Kalmar, samt att mäta inställningen till den allt mer krympande svenska handelsflottan. För att genomföra detta arbete användes en enkätundersökning där förstaårsstudenterna på det fyraåriga sjöingenjörsprogrammet utgjorde populationen. Resultatet i undersökningen visar att möjligheten att få utveckla sina praktiska färdigheter var av stor betydelse vid utbildningsvalet. Andra faktorer som värderades högt var ett intressant utbildningsinnehåll och intressanta arbetsuppgifter efter avslutad utbildning. / The Swedish merchant fleet has in the past years been subject to flagging-out which has forced many mariners to go ashore or look for work under a foreign flag. Despite the problems with flagging-out and a potential reduction in the labour market the marine engineering programme has over the previous years not faced any major problems to fill up their training positions. The future remains uncertain as competition from other shipping nations increases significantly. The purpose of this study was to investigate the underlying attitudes and expectations that made students in 2013 choose to study the four -year marine engineering programme at the Kalmar Maritime Academy. Furthermore the study investigates the students attitudes towards the shrinking Swedish merchant fleet. To carry out this investigation, a survey was made among the first year students on the marine engineering programme. The results of the survey show that the opportunity to develop the student’s practical skills was of great importance in educational choice. Other factors that were highly valued were an interesting educational content and interesting job tasks after graduation.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Cover title. "June 2002." AD-A404 869. Includes bibliographical references (p. 73-79). Also available via the World Wide Web.

Nesta tese, nós apresentamos uma compilação de três artigos de otimização aplicados no contexto de transporte urbano de ônibus. O principal objetivo foi estudar e implementar heurísticas com base em Pesquisa Operacional para otimizar problemas de (re)escalonamento de veículos off-line e on-line considerando várias garagens e frota heterogênea. No primeiro artigo, foi proposta uma abordagem heurística para o problema de escalonamento de veículos múltiplas garagens. Acreditamos que as principais contribuições são o método de geração de colunas para grandes instâncias e as técnicas de redução do espaço de estados para acelerar as soluções. No segundo artigo, adicionamos complexidade ao considerar a frota heterogênea, denotada como multiple depot vehicle type scheduling problem (MDVTSP). Embora a importância e a aplicabilidade do MDVTSP, formulações matemáticas e métodos de solução para isso ainda sejam relativamente inexplorados. A principal contribuição desse trabalho foi o método de geração de colunas para o problema com frota heterogênea, já que nenhuma outra proposta na literatura foi identificada no momento pelos autores. Na terceira parte desta tese, no entanto, nos concentramos no reescalonamento em tempo real para o caso de quebras definitivas de veículos. A principal contribuição é a abordagem eficiente do reescalonamento sob uma quebra. A abordagem com redução de espaço de estados, solução inicial e método de geração de colunas possibilitou uma ação realmente em tempo real. Em menos de cinco minutos, reescalonando todas as viagens restantes. / In this dissetation we presented a three articles compilation in urban bus transportation optimization. The main objective was to study and implement heuristic solutions method based on Operations Research to optimizing offline and online vehicle (re)scheduling problems considering multiple depots and heterogeneous fleet. In the first paper, a fast heuristic approach to deal with the multiple depot vehicle scheduling problem was proposed. We think the main contributions are the column generation framework for large instances and the state-space reduction techniques for accelerating the solutions. In the second paper, we added complexity when considering the heterogeneous fleet, denoted as "the multiple-depot vehicle-type scheduling problem" (MDVTSP). Although the MDVTSP importance and applicability, mathematical formulations and solution methods for it are still relatively unexplored. We think the main contribution is the column generation framework for instances with heterogeneous fleet since no other proposal in the literature has been identified at moment by the authors. In the third part of this dissertation, however, we focused on the real-time schedule recovery for the case of serious vehicle failures. Such vehicle breakdowns require that the remaining passengers from the disabled vehicle, and those expected to become part of the trip, to be picked up. In addition, since the disabled vehicle may have future trips assigned to it, the given schedule may be deteriorated to the extent where the fleet plan may need to be adjusted in real-time depending on the current state of what is certainly a dynamic system. Usually, without the help of a rescheduling algorithm, the dispatcher either cancels the trips that are initially scheduled to be implemented by the disabled vehicle (when there are upcoming future trips planned that could soon serve the expected demand for the canceled trips), or simply dispatches an available vehicle from a depot. In both cases, there may be considerable delays introduced. This manual approach may result in a poor solution. The implementation of new technologies (e.g., automatic vehicle locators, the global positioning system, geographical information systems, and wireless communication) in public transit systems makes it possible to implement real-time vehicle rescheduling algorithms at low cost. The main contribution is the efficient approach to rescheduling under a disruption. The approach with integrated state-space reduction, initial solution, and column generation framework enable a really real-time action. In less than five minutes rescheduling all trips remaining.

[pt] O custo de transporte marítimo representa o elemento mais importante em termos de custos logísticos para a PETROBRAS. O atendimento pleno de seu mercado de derivados de petróleo somente é possível através da manutenção de uma frota de navios próprios e contratados, que navegam e operam por toda a costa marítima brasileira, além de buscarem produtos em outros países. Neste sentido, esta dissertação propõe um modelo de programação linear inteiro misto cujo objetivo é dimensionar o tamanho da frota e o porte dos navios para o transporte de derivados claros restritos à navegação de cabotagem. O modelo proposto baseia-se em um modelo existente na literatura, e seu resultado auxiliou os programadores a definir quantos navios são realmente necessários para atender os compromissos assumidos dentro de um horizonte de planejamento pré-estabelecido. Comparando este resultado com o número de navios já contratados e disponíveis para programar, pode-se, eventualmente, liberar navios para realizar viagens de longo curso, evitando assim a contratação de navios em Voyage Charter Party para este fim, além de reduzir a sobreestadia nos períodos de baixa movimentação, quando a frota contratada torna-se superdimensionada. / [en] The shipping cost is the most important element in terms of logistic costs to PETROBRAS. The full attendance of its oil products market is possible only by maintaining a fleet of own and hired ships that sails and operate throughout the Brazilian coastline besides loading products in other countries. In this sense, this dissertation proposes a model of mixed integer linear program whose objective is to determine the coastal navigation fleet size and the type of vessels to transport clean petroleum products. The model propose is based on a previous model from the literature, and its outcome helped programmers define how many ships are actually required to meet the commitments undertaken within a pre-established planning horizon. Comparing the model s result with the actual number of vessels available for programming, one can eventually release ships to make other journeys, thus avoiding the hiring of ships in Voyage Charter Party for this last purpose. It is also possible to reduce the demurrage in periods of low movement, when the fleet contracted becomes oversized.

Nesta tese, nós apresentamos uma compilação de três artigos de otimização aplicados no contexto de transporte urbano de ônibus. O principal objetivo foi estudar e implementar heurísticas com base em Pesquisa Operacional para otimizar problemas de (re)escalonamento de veículos off-line e on-line considerando várias garagens e frota heterogênea. No primeiro artigo, foi proposta uma abordagem heurística para o problema de escalonamento de veículos múltiplas garagens. Acreditamos que as principais contribuições são o método de geração de colunas para grandes instâncias e as técnicas de redução do espaço de estados para acelerar as soluções. No segundo artigo, adicionamos complexidade ao considerar a frota heterogênea, denotada como multiple depot vehicle type scheduling problem (MDVTSP). Embora a importância e a aplicabilidade do MDVTSP, formulações matemáticas e métodos de solução para isso ainda sejam relativamente inexplorados. A principal contribuição desse trabalho foi o método de geração de colunas para o problema com frota heterogênea, já que nenhuma outra proposta na literatura foi identificada no momento pelos autores. Na terceira parte desta tese, no entanto, nos concentramos no reescalonamento em tempo real para o caso de quebras definitivas de veículos. A principal contribuição é a abordagem eficiente do reescalonamento sob uma quebra. A abordagem com redução de espaço de estados, solução inicial e método de geração de colunas possibilitou uma ação realmente em tempo real. Em menos de cinco minutos, reescalonando todas as viagens restantes. / In this dissetation we presented a three articles compilation in urban bus transportation optimization. The main objective was to study and implement heuristic solutions method based on Operations Research to optimizing offline and online vehicle (re)scheduling problems considering multiple depots and heterogeneous fleet. In the first paper, a fast heuristic approach to deal with the multiple depot vehicle scheduling problem was proposed. We think the main contributions are the column generation framework for large instances and the state-space reduction techniques for accelerating the solutions. In the second paper, we added complexity when considering the heterogeneous fleet, denoted as "the multiple-depot vehicle-type scheduling problem" (MDVTSP). Although the MDVTSP importance and applicability, mathematical formulations and solution methods for it are still relatively unexplored. We think the main contribution is the column generation framework for instances with heterogeneous fleet since no other proposal in the literature has been identified at moment by the authors. In the third part of this dissertation, however, we focused on the real-time schedule recovery for the case of serious vehicle failures. Such vehicle breakdowns require that the remaining passengers from the disabled vehicle, and those expected to become part of the trip, to be picked up. In addition, since the disabled vehicle may have future trips assigned to it, the given schedule may be deteriorated to the extent where the fleet plan may need to be adjusted in real-time depending on the current state of what is certainly a dynamic system. Usually, without the help of a rescheduling algorithm, the dispatcher either cancels the trips that are initially scheduled to be implemented by the disabled vehicle (when there are upcoming future trips planned that could soon serve the expected demand for the canceled trips), or simply dispatches an available vehicle from a depot. In both cases, there may be considerable delays introduced. This manual approach may result in a poor solution. The implementation of new technologies (e.g., automatic vehicle locators, the global positioning system, geographical information systems, and wireless communication) in public transit systems makes it possible to implement real-time vehicle rescheduling algorithms at low cost. The main contribution is the efficient approach to rescheduling under a disruption. The approach with integrated state-space reduction, initial solution, and column generation framework enable a really real-time action. In less than five minutes rescheduling all trips remaining.